Advances in semiconductor processing and logic design have permitted an increase in the amount of logic that may be present on integrated circuit devices. As a result, computer system configurations have evolved from multiple integrated circuits in a system to multiple hardware threads, multiple cores, multiple devices, and/or complete systems on an individual integrated circuit. Additionally, as the density of integrated circuits has grown, the power requirements for computing systems (from embedded systems to servers) have also escalated.
Power and thermal management issues are considerations in all segments of computer-based systems. While in the server domain, the cost of electricity drives the need for low power systems, in mobile systems battery life and thermal limitations make these issues relevant. Optimizing a system for maximum performance at minimum power consumption is usually done using the operating system (OS) or system software to control hardware elements. Most modern OS's use the Advanced Configuration and Power Interface (ACPI) standard (e.g., Rev. 3.0b, published Oct. 10, 2006) for optimizing the system in these areas.
Many computer systems may often require a surge of power well above normal design limits of most power regulators when in a higher frequency/performance state, generally referred to as a turbo mode. To handle the surges, most systems provide a costly over-design of the voltage regulator. Sudden power loads in computer systems also produce transients in the system's power supply, which can cause issues with proper system operation. This is usually remedied with the addition of bulk output capacitors. However, this is an expensive method of resolving the issue.